diff --color-moved-ws: fix false positives

phillipwood · gitster · commit 2034b473e131 · 2019-01-10T10:38:08.000-08:00
'diff --color-moved-ws=allow-indentation-change' can color lines as moved when they are in fact different. For example in commit 1a07e59 ("Update messages in preparation for i18n", 2018-07-21) the lines - die (_("must end with a color")); + die(_("must end with a color")); are colored as moved even though they are different. This is because if there is a fuzzy match for the first line of a potential moved block the line is marked as moved before the potential match is checked to see if it actually matches. The fix is to delay marking the line as moved until after we have checked that there really is at least one matching potential moved block. Note that the test modified in the last commit still fails because adding an unmoved line between two moved blocks that are already separated by unmoved lines changes the color of the block following the addition. This should not be the case and will be fixed in the next commit. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Reviewed-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.c b/diff.c
@@ -1106,10 +1106,10 @@ static void mark_color_as_moved(struct diff_options *o,
 			continue;
 		}
 
-		l->flags |= DIFF_SYMBOL_MOVED_LINE;
-
-		if (o->color_moved == COLOR_MOVED_PLAIN)
+		if (o->color_moved == COLOR_MOVED_PLAIN) {
+			l->flags |= DIFF_SYMBOL_MOVED_LINE;
 			continue;
+		}
 
 		if (o->color_moved_ws_handling &
 		    COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
@@ -1143,10 +1143,13 @@ static void mark_color_as_moved(struct diff_options *o,
 			block_length = 0;
 		}
 
-		block_length++;
+		if (pmb_nr) {
+			block_length++;
 
-		if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
-			l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
+			l->flags |= DIFF_SYMBOL_MOVED_LINE;
+			if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
+				l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
+		}
 	}
 	adjust_last_block(o, n, block_length);
 
